Zone metering telephone exchange system



Nov. 3, 1931.

W. -HATTON ET AL ZONE METERING TELEPHONE EXCHANGE SYSTEM Filed March 8, 1930 III 7 Sheets-Sheet 1 /NVENTO/?S w HA TTUN 0. DE vR/E/vUf' E. u. fioussg-A u Y 914% A r TOHNEK Nov. 3, 1931. w. HATTON ET AL 1,329,799

ZONE METERING TELEPHONE EXCHANGE SYSTEM Filed March 8, 1930 7 Sheets-Sheet 2 WHATTON INVENTORS C. DE VR/END T E J. ROUSSEAU Nov. 3, 1931. w. HATTON ET AL 1,829,799

ZONE METERING TELEPHONE SYSTEM Filed March'- ;3a fll93o 7 Sheets-Sheet 5 I D l] D [1 u u u n u n n u u n u u D l] D D D D U D D n u n u n D U U [1 U u u u n n u n u u n u u u n u U [l D D [I U I] D U WHATTON INVENTORS 0. DE VR/ENDT E. J. RDUSSEAU Nov. 3, 1931. w. HATTON ET AL 1,829,799 ZONE METERING TELEPHONE EXCHANGE SYSTEI Filed March f8, 1950 '7 Sheets-Sheet 4 W HA TTUN WVENTORS 0 DE VHIENDT E. d. ROUSSEAU BY 26am 4 Tram/ Nov. 3, 1931. w. HATTON ET AL 1,329,799

ZONE METERING TELEPHONE EXCHANGE SYSTBI Filed March 8, 1930 7 Sheets-Sheet 5 W HA TTON lNVE/VTORS 0. DE VR/ENDT E. J. ROUSSEAU ATTORNEY Nov; 3, 1931. w. HATTON ET AL 1,329,799

208E METERING TELEPHONE EXCHANGE SYSTEM Filed March 8, 1930 7 sheets sheet 6 M. HATTDN INVENTORS C. DE VR/ENDT E. J RDUSSEAU Nov. 3, 1931. w. HATTON ET AL 1,829,799

ZONE METERING TELEPHONE EXCHANGE SYSTEM Filed March a, 1950 '7 Sheets-Sheet 7 uunu nnnn nnuu mung] [IDEIEI n-nun nun uuunn uuuun unuun umnnn uuunn nun-nu UDDIJEI nuunu r uunnn W HA TTDN //Vl EN7'0/?5 C. DE VR/ENDT E. 1- ROUSSEAU i Patented Nov. 1 931 lm'rso su s PATENT OFFICE v wi LiAivi Hams, cnanii'iis 'im viiiEivii'r, AND ERNEST JEAN BOUSSEAU, or PARIS;

J' i iiiiiucs,fiissieivon s To WESTERN nnnc'rmo COMPANY, :V'VYOBK, N. n, A:CORPOE-ATIO1\T QENEW YORK INCORPORATED, OF NEW Y fzoiiniunrnniive TELEPHONE EXCHANGE SYSTEM 9 Application filed March 8, 1930, Serial no. 434,21 and in Great Britain March 18, 1929.

.This invention relates to automatic telephone systems, and-more particularly to a rural exchange system comprising district offices grouped around a tandem ofiice,the

fi'tandem oifice in turn being subsidiary to a central oficegln such a system it is desirable that the charges for calls originated on lines either local to a district ofiice or local to a tandem otfice 'beassessed in accordance 10 with whether the call is to be terminated locally in either the district oflice-or in the tandem ofilceor is to be terminated outside or": said offices. It is,'therefore, the object of the invention to provide at each oflice 5 of the system a discriminating device which is common to the trunk circuits outgoing fromsuch office and which is capable of de terinining whether a call originated in such oiiice is ot a'localor of an interoliicecharactor and whichw-ill if the originatingcall iso'li the latter character cause the operation" ofthe calling line message registerin accordance with the zone of the exchange area in which the call-is terminated. The invention, one embodiment of which has been disclosed byway of example,is illustratedas embodying a district'ofiice which is subsidiary to a tandemoffice and which through the circuits of-the tandem ofiice may 0 have access. over the trunk circuits outgoing.

"from the tandem o'fiice, to a central ofiice. The district ofiice is designed tohave access "toi'rom 100 to 300 local subscribers lines-and I toa group of trunk lines extending tothe tanc em ofice. Itisprovidedwith a plurality oflink circuits, eachilink terminating at one end infa line finder and iat the other end in a plura'lity of branches each having a group selector. Thus; ifthel oifice is'designed for access to 200 lines certain of which are trunk lines extending to the tandem oific'e, each link will terminate in two group selectors and if access is; desired to} 300 lines, 'each link circuit will terminate: inthree group selectors When a subscriberofthedistrict office initiates a callallline ,findersof idle links having access theretfo are started in. search of the calling lineand when one'ofthe line 59 finders finds the line it .is seizedthereby and the finders of other links are stopped. Thereupon that one of the group selectors of the link taken for use which has access to outgoing trunks is started in search of an idle trunk. When an idle'trunk becomes associated with the link circuit a discriminating registering device which is common to the group of trunks is associated withthe trunk taken for use in readiness to record the first three digits to be dialed by the calling subscriber. Also, in response to the seizure of the outgoing trunk an idle link circuit at the tandem office which is also equipped with a line finder and group selector is started to find the trunk and to extend it over the group selectorof the tandem oiiice link to an idle trunk outgoing from the tandem ofiice. When another subscribers line which terminates at :the same oflice, a discriminating signal is sent-to the link circuit of the district ofiice from the registering device of that oifice.

This signal determines whether the wanted line may be reached over the terminal bank of the same group'selector over which access washad'to the outgoing trunks or-whether it may be reached over' one of the other parallelly connected group selectors, and renders marking registers efi'ective in the link circuitfor recording the remaining digits of the line. designation dialed by'the calling sub-' scriber. In accordance with the setting of the marking registers the group selector which has been made effective by the discriminating signal is thereupon operated to select the wanted line and to release the connection over the outgoing trunk previously established through the tandem oflice and to release the associated discriminating de vices at boththe district and tandem ofiices.

"Upon'the termination of the call the calling subscriber is charged by. apparatus associated with the district link circuit on the basis of a successful local call.-

i If, however, the digitsrec t 7.61157 criminating registering devices of. the dist'rict 'andtandem oflices indicated that the call was of a ,characterjto be terminated in" or be-;

yond the tandem ofiice, then the connection established upon the initiation ofthe call to the tandem officeis notreleased and the dis-F crlminating registering device of the district,

ofiice proceedsto set up on registering relays oftheoutgoingtrunk with'which it is at-the time associated a zonelregistrationin accordance with the office designation registered "on the register-sotisaidregistering device.

These zone relays are instrumental upon the There is also associated with the zone re lays of the trunk circuit an overt me charging mechanism which causes the periodic opera- .tion of the calling line message register through a'predetermined maximum period of I conversation. Inthe circuits illustrated this overtime charging mechanism functions to "operate the message register at three-minute intervals over a period-of twelve minutes and I theg ';roup selectors and at the right one outthentausesthe peremptory release of the connection ifa-the calling subscriber" has notthat 'P'GIlOd re-' prior to theeiipirati'on of leasedthe connection. 1 I a Similarly, 1f 'a'call 1s originated on a subscribers line terminating in the tandem ofice all line finders vof idle linksof the tandem ofiicewhaving-access'thereto are started in search of suchline and when one of the line seized and the finders of other links are stopped. Thereuponthe group selector in which theotherend ofthe link circuit ter minates is operated to connect with an idle f three digits dialed by a calling subscriber together with a; trunkfinder switch, shown in. theupper portion of the figure, whereby the registering device may-be associated with trunk outgoing from the tandem ofiiceand discrim nating registering devlce 1s associated with such'trunk in'readiness to record the first three digits dialed bythe calling sub 'scriberl} 'Ifthe first threedigitsfdialed' thecalling subscriber indicate'that-the-call' ingysubscriber desires a; connection "with anether subscribers line which terminates in the tandem office, a signal is sent back to the tandem oifice link, which causes the re- 'lease of the outgoing trunk circuit and as- 7 'SCriberJ- 1 If, however, the digits recorded in the 'reg-[ istering device indicate that the call is of a character to be'terminated beyond the tanvice; upon the successful completion of the connection for variably op'eratingfthe mcssagere I ister'of the calling-linen Provision is also *"made tocharge for the "call periodicallydurdem otfice, then the trunk is not released V the registering device of the'tande'm" ofiice proceeds to setupon thejregist ering relays of the outgoing trunk a zone registration in accordance with the office designation registered-on the registers of. such: registering de- Thcse zone relays are; instrumental ing a predeterminedperiodand to peremptorily release theconriectio'n at the expiration ofjthat period if the calling'subscriber has not terminated theicall.

7 From the foregoing brief description-of the invention 'itfwill' be apparentthat for a i call originated in any .ofiice which is of; an

interofiice character charging. on an over time bases inaccordancewith the zoneof the exchange inwhich the 'call-i s'tobe terminated controlled by the apparatus in the oflic'e of the other Iend'in a plurality ofparallelly con[- nected groupselectors, tens and units marking switchesfor'controllingthe settings of" going trunkw circuit and awsubscribers line terminatingin the bank of one'of' the group selectors. d

.Fig. '2. shows the apparatus associated with the outgoing. end ofthe. trunk circuit and in the lower rightportion of the figure a message'register impulsing'switch for-controlling thecalling line message register of ice 1 in accordance with the zone of-the eX- change into whicha connection isex'tended;

. Fig. 8- shows afdiscriminating registering device for recording andtranslating thefirst any one of'a group of trunkcircuits v 2, one of the link circuits of the tandem ofiice terminating at one end'in "a line finder hav-i ing'ac'cess to both incoming trunk circuits and'subscribers lines and at the other end in a group finder having access to'outgoing trunks such as shownin- FigY-G and to local thirdgroup'finderstnotshown). Fig. 5' shows 1a tandem register sender for controlling the establishment foffconnections to subscriberslines terminating in the tandem oflice and a link finderindivl'dual thereto" for associating itwith atandem link circuit. Fig; i 6: shows an outgoing trunk circuit mama; iowenrightaportiomof thefigureiay device for recording'andtranslating theflfirst, f r three digits dialed byiazcallingsubscriber in 7 either the district ofl'ice of Fig. 1- or; in the message'L-regiStenimpuIsing switch for con:-

' V trolling the message registersoficallingilines which are local rtoithei tandem' oflice Fig. 7" SllOWSgfii discriminating registerings tandem. office, together with trunk finder switch individual :thereto,' wherebythe reg- V istering devicemayibesassociated with. any one ofthe outgoing trunkicircuitsisuch as f theitrunkF circuit shown inJFig. 61"

' u Fig. 3 'beneathFigJ2, Figs. 1 and 5:;atthe I Y 6- and 7" at the tivelvr V For acompletedisclosure of the invention: Fig. 2 shouldbej placed at the right 0t Fig.1,

right "of Figs; 2' and3," respectively, andiEigs; rightiof "Figs, and 5, respec'-" All of the syvitchesdisclosed" are of the single motion step-by-Step: type-The line findersIOOand a00iof F-ig's; 1 and-Aareof: the type havingno normal position andieac-hn: is equipped with two sets ofwipers placed on the switch shaft-180 apart. l he group selectors "110,1120-"a11d,1300f Fig. 1 are of I I the same general type asthe line findersfand 'each ha-s access toone hundred sets of banks terminals; The group selector11'0hasaccess to a group of five o utgolng trunks and to; ninety subscribers lines and the other two.

groupselectors 1'20" and Y130, the wipers of selector 130'n'otbeing illustrated, each have regist ers e10, 320,510,520'g530, 710 21:16:72.0

access to one hundred subscribers lines; The group selector 410 of Fig; 4: is of the hunting type. "The markingswitches 140,150, the

' andthe message register "iinpi'il's'ing switches a 200, tee and 600' are allminor type switches.

1 iii :The translator switches 330,540 and -7 each have access to fifty sets; otbanlr terminals,

I the terminals of the uppenfour levels of switch .330 being cross-connected, as-may' be desired, to the cross-connecting rame 34c0 c for controll ng metering for establishing local connections, v and the upper four levels of swltch 730 being cross cojnnected, as may be desired to cross connecting fra1ne-74OQfor positions; j

controlling metering. I The trunk 1 finding; sivitches300, 500 andZQO have no normal Initiation of it caught For a bett'er understanding of the inven tion reference may bei'had 'to' the following description in which theprogressof'a call from the calling line lOl over the circuits of Figs; 1 to 7 inclusive, will first bedescribed 1 in detail. When :the calling subscriber 'rejmoves his receiver from the s'witchhook a" circuit is established from battery, through the Winding of line relay 102, theiupper back" contact of cut-off rela'yf103, over the loop of the calling'line'to grourid at the lower contaet ofr'elay 1031 -Belay 1-02 upon operating relay 108 -to groundiat the establishes; an obfvious circuit for the common grouprel'ay 104 which in turn establishes. agfcircuit for:the common line finder start; relay; 105i Relay 105 :at its front contacts, closes start circuits for the stepping magnetsiof all idle line finders having access to the group ofline's in hich the calling line islocated, It will be assumed that the line finder 100 isthat one of these line finders Whichis to, be used in establishing the con? nection. The-circuit for starting this line finder may be traced trom'battery, through of stepping magnet 106, contacts of relay 105;contactsoftest"jack.107, back contact of upper normal contactsofrelay 109,

-. Inresp'on'se to the operation of magnet 106,

e the Wipers of theline finder areadvanced until the testwiper lllengages the test terminal of the calling ,line. Then a-circuit is established from ground, throughthelower in'dingofrelay 108, the normal contact of thermostatic relay 112,contacts of jack 107, Wiper 111 tobattery at the front contact of relay 102. Relay 1O8 upon energizing' closes an obvious circuitfor relay 113 and opens at its back contact the circuit of stepping magnet106. v, With relay 113 operated, ground is connected over'the lower. contact ofrelay 113.

and the 'upper winding of relay 108 to test themagnetfwinding'andinterrupter contacts 1 Wiper 111 to prevent the seizure of the calling-line-byother line finders and a circuitis closed 'for the stepping magnet, 11a of the.

' group, selector- 110-'to advance this group selector to hunt for an idle-outgoingtrunk;

-This circuit extends from battery, through the Winding and interrupter contactsof magnet 114,1bwerback contacts of relays 115 and;

116,1owerback contact of relay 109, upper i be described later. 1

VRelay; 117"upon, operating, opens the c'ircuit'of magnet 1'14 to arrest the operation of the group selector 110 and establishes over its front contact and a contact of relay 113 a circuit for relay 123. At its innerv lower frontcontactrelay 123 applies direct ground throughthe winding ofrelay- 117 over Wiper 122 to conductor 201to marklithesel'ected trunk busy and closes an obvious circuit for relay 124 Relay 12 t upon operating estab lishes acircuitfromground through the Windingoi-relay: 109 ,over Wiper 12,5 of line 1 100 tobattery through the-calling line" c'utf-ofirelay 108,- Relay 1'03disc0nnects the" or linerelay 102*which-in'turn releases relay l 51,08 and if there are atthe'time' m; other linesY V ifcalling in thegroup,' releases comnion'relays i I 104 and 105-thereby-arresting theoperation or any other fidle line'finders that may have been-started. After the releasefof relay" 108,

v relay'113 is looked over its inner-lower front &contact', {the back contact of relay-126 to at the upper frontcontact of ?relay.

I ground I Relay -202 of the link-circuit Which operated.series yvithtestrelay 117 [upon operat 'iing establishes an obvious circuit for relay 203. -Withrelay 109 operatedacircuitl is:

t flestablish'edfrom ground, through the upp er winding of relay 204, Wiper 127- of selector 110," upper alternate contacts'of relay 123,

i 1 21) lower front contact of relay 1'09, Wiper 128, over? the calling line, loack over Wiper 129 ,1 the inner uppercontact'of relay 1;09,'the inner upper front contact of relayjl23, wiper 131 'to battery throughthe lo'wer 'winding o t re; 25'': lay 204. 'Relay204 operates in thi'scircuit and closes'anoloviouscircuit forslowfto re lease relay 205 'Which operates-in turnand causes the operation" of relay- 206; A circuit a V is-nowextendedover theoutgoingconductorsf 380* 207 and 208 of the trunkjcircuit to the ta'ndeinf-f community oifice is subsidiary, this circuit eX- I iupper-normal contacts of rela'y 417 M tending frombzittery, through the winding vof relay-401,}the' lower bac'k contact of relay.

359402 over'conductor" 208, t'he backcontact-of relay 210, the lower back contact of relay-209,

upperjfrontgcontact of relay' 204, conductor 207' to ground at the upper back contact of relay 402, l-Rela'y 401' operates in this circuit '40 and at its upper front contact closes an ob -1 vious circuit for common start relay 403 and at its lower trout contact connects battery- ,potential to the test terminal 404to mark the "trunk 207, 208 asc'allingr Relay 403; upon 7 operating closes start circuits for all idle line finders such as400, which have access to the lineis located.

3:11} Will be assuniedthat the line finder 400 group oftrunk circuits 'in Which the calling r relay 503 which in'turn establishes operat- 7 'i g' i c its o i ev s pp ng g e r all so is to be used to extend the connectio'nand' that the start circuit for magnet 405 extends from battery through'the Winding andinter-i rupter contacts of Inagnetf405, contacts of test ack 406,- contacts of relay 403, back-con= .f tact of relay 407 to ground at theloack contactof test relay 408.? When the Wipers of the linegfinder engage the terminals'of: the" calling trunk circuit test relay 408 operates c in 'acircuite tendingfromhattery on ters -iniinal 404, Wiper 409,- contacts ofz'ja'cki 406,

- inorni'al'icontacts.of thermostatic i'relay 411' .tof ground through the upperwinding ofrei.

lay 4O8, Relay-408 operates, opening the cir- M "cuit of 'Inagnet 405 to arrest further motion 7 ft 'of'line finder 400 andcloses a 'circuit for 0p tact of "relay 413; At-Lits i erating' frelay-i-412i eirtending.lirofiigground at the fro tico tactef l yf4 pg r- W wk 1 er upper' front ing'iofirelay- 412 to} battery; atgthe operating" relay. 414 extending from. battery, through thel'winding ofrel'ayi 414, the contact.

of relay 412 150v groundat thefr'ont contact 'otrelay'408l At its contactrelay- 414 establishes: a circuit extending'sfroln ground through thewinding-ofrelay 407 wiper 415 to c b'att,ery, thro.ugh thejwinding of .cut-ofi' relay -"402; Relay402l disconne'cts the line relay 401 from'theztrunkcircuit, which upon releasing opens thecircuit of .commonstart relay403 to stop all other-line finders which ma have i'heen started, provided that there are at thetimeno other trunks of the group or subscribers lines calling Belay'402 also closes an operating circuit for slow to release relay 4'16 extending from groundthrough-the "Winding ofrelay4lj6, lower back contact: ofgrelay 417, front contact; of:-;relay 402, to Y battery; Relay 4l6fop ens1 the trunk con ductor 208 at itsback contact, but this open- ,ing at the ,timeeinefiectiv since a shunt of thecontacts of relay '416'{e'xists over the Relay "407 o upon-s operating extends the trunk conductor 207 io'yer; line finder wiper;

418, theupperfront contact of relay 407 the upper I back contact of' relay 421 to 1 ground through the flowerlwinding of relay v422 and V at; its intermediate upper' front contact extends 1COIldllCtOi 208OVer Wiper 419, theloWer loack contact of relay} 421 to battery through the upper Winding of relay 422. IAt its lowerfrontcontact relay 4 12 connects Inarkingcpoc '-tenti a-l to test terminals 501 ofall link finders similar to'finder 500 of; Fig: 5 and in parallel: t0 ground through;-start relay 502. Relay 502 operated-closing an olovious; circuit for idle link finders individualfto idle tandem senders. One. of these sender is' shown in Fig. 5 and itlwill be assuinedthatlthis sender 50 4, contact of relay 503, upper-back 'contact of relay 507 to, ground atthe back contact; of

relay 5 05, W-hen the calling link circuit is found, jtestWi-per 506' of finderi500 engages terminal I 50 1,?) and the 'circuit previouslyv traced toTtcrminal 501isextehded over. wiper 506,;the upper Winding ofvtestrelayz50 5, the 'lowerloack Contact" otrelay. 508 toground at the nor nal contactjof thermostatic relay Relay505ithereupon operates, opening atlits' back'contact-the;circuit of magnet 504 andclosing an obvious circuit for relay 512 which: in turn closes an obvious circu t, for

relay 507. Relay 507 vat itsinner upper front contact now connects ground through the lower low resistance winding. of relay 505 to I testfternnnal' 501and at it's 'upper back con tactopens another; point infthe circuit of magnet 504. At its: inner upper front contact relay 507' connects ground, to conductor. 55-3401 supplyinglocking ground for relays of the sender'and at its lower front contacts prepares'circuits from wipers. of finder, 500.

Atits lower i front contact.- relay 407- also establishes i a circuit extending through the lower winding of relay 413, wi er 511 oflink finder 500, bothewin'dings o relay--513"to ground. onconductor Relay513 operates butperforms nolusefulfun'ction at th1s't-ime. Relay 413 does notioperate'due to the T681804 ance of thevwindin'gs 'of relay 513.

Q'When re-lay'v407f, operated a circuit was established for starting 'the group selector 410 hunting for an outgoing trunkv circuit such as 18 showninFig. 6,wh1ch circuitrnay beftraced from battery through the winding and interrupter contacts of magnet 423, in-

- termediate. upper back contact of relay'424,

back contact" of" relay 425 to ground at the inne'rupper front contact of relay 407; When I anidle outgoing trunk is found,for:example,

the trunk shownin Fig. 6 relay 425 operates in .aV-circu'it extending froin ground on the f'innerupperfront'contact of relayj412, low-v er windingf relay'425,.upper back contact Relays 425andf 5 operate} relay 7425 upon v operatinglocking' from battery on; test wiper 427 over its upper windingthrough, the windi-ng of relay 428, the front contact of relay 425 to ground at thei'inner upper front contact of relay 407; and opening at its back contact the circuit of magnet 423 toarrest the further hunting movement of the I group I selector; -Atits contact relay 428 closes an obvious circuit for relay 429 which operates 4 and locks over 11 31111116! lower front contact to: ground placed onconductor 430 over the front contact'of relay 414." Relay'605 upon operating closes an jobvious circuit forrelay606.; I

7 Relay 602 now operates in'a circuitxextending frornvgroundfat the lower backcontact of 5 relay; upper front contact of relay 606, lower: winding" of relay [602,"coi1ductor; 616,

' Wiper inner upper normal contacts of rela I to bat necting battery through its upper winding 426,; upper front Contact of relay 429;

through the winding of relay-421. Relays :602 a-ndf421 o ae'rate relay' 602mmand 'front-fcontafct in parallel with battery through resistance overthe upper back con- ;tact ofre'lay' 615 to conductor 601 to mark the trunk busy to other tandem link group selectors and relay 421 disconnecting the windings-of. relay 422 from the incoming dialing loop and extending this loop over its upper'andtlower front contacts directly to' V thewindingsrof relay 604..., At its inner l0'w-. 'er front contactrelay 421 establishes a new holdingtcircuit for holding relay 414 operated iafterf the release of relay 422; 4 Relay 604 now operates establishing-a new operating circuitfor relay605 which in turnholds relay606 operated;

,pReturning to themt'runk circuit of Fig.2, relay v206Tupon'operating at its. inner upper contact connects busy potential from the up: per Lbackcontact of relay 215 over the normal contacts of thermostatic relay 217, resistance 218, contacts of relay 206 to conductor 201' in parallel with relay 202 for holding relay 1170f the districtlink circuit operated. At its innermostlower front contact relay 206 connect s--marking potential over the lower back contact of relay v211, the inner lower frontfcontact of relay 206 to test terminals 301 of all trunk jfinders'similar to trunk'finder 300 ofFig. 3 and in parallel to ground through start relay302. 9 Relay 302 operates .closing-an;obvious circuit for relay 303 which in turn establishes operating circuits for 'the stepping magnets of all, idle, trunk finders individual to idle registering devices. One'o'fthese'registering devices is shown in Fig. 3 and it will be assumed that this registering device is idle and becomes connected :with thetru'nk of Fig. 2:- The operating cincuit of trunk finder 300 of this registering device may be 1 traced from battery, through the winding-and interrupter-contacts of steppingmagnet 304, a contact of relay 303 its toground at the back contact of relay 305;

Whenythewalling trunk is found and test wiper 306:10fl3l1111k finder 300 engages termi nal 301, the circuit previously traced to ter minal 301 is extendedover wiper 306, the upper winding of'relay 305 to ground atthe normally closed contact. of the ofi-normal springs 354' of translator switch 330. Relay 305 thereupon operates opening the circuit of magnet 304 and closes an obvious circuit for relay 307 which at its lower front contact connects the low resistance winding of relay 305' intocircuit withwiper 306 to busy the trunk. circuit to other trunk finder switches. 1 i y e Q-Relay307 also closes a circuit in parallel throughthefwindings offrelays, 210, and 211 ovenflwip'er 308;? the innermost upper front to 'ground at the-back contact of relay 312-. Relay" 210- Q'perates to close'the' outgoing "thev discriminating; registering device ef Fig; and t6 establish 1 an eutdialingllo'op- Over V )fcondfictbrs 60Ze'iidi608 underthecontrol of g' -impulse"repeatingrelay 6041 "This dialing 1 loop may, for examplefe xtend to' a central ofiicete which: the tandem fiiceis subsidiary Upon thel'conne'ctionof'the registering detice of Fig. 7: relayffi'lQjeperates in the sameeireliit so t-hat the, vrin'iy re? Y Genre a dial -t'ne"incoming over} the "trunk circuit; {Relay 211 being marginal does not, he'weverfoperate atthisitinie' becauseof the resistance 355'in its; operating bircuit- The' continuity-0f the loop-cireuitbver'the 01kt gbing trunk" circuit isg-not, however, brbken V operation ofrelay :210 since it is main "mgtained' through the winding of: supervisory 'Fbllowinggthe seizure of the-trunk. circuit .e f' -Fig;16 itif1incti0ns in identically the-same liniiinen ust deseribjed i111 connection With Fr day-212.;

Y Fig; 2't0 cause the association therewith 'ofmanner as "relay '21O a-nd; extends'trunk-een thrdugh I condensers 631 and: 632, the wipere 4345 and-431,front conta'cts"ofrelztys 421 and 4107, ipers 118 and 119, trunk 'condilctors'v 207 and 208, front contacts of relay 21O,';c 0n

densers 231; andj'i232, wipers 127 31101431,

apparatus associated-@with' the distant end I i V .Qfitrunk reedy te receive impulses;

v i WhePn siihscrihed receives Q dialing tene he i proceeds i170 dial the 5 digits 1' of the fwafnted line"numberr It: Willjbe' e sreached locally overthewipersfot the group Iselector 11O fpf Fig1f lln response to diel ain jthe1first digitiseven, the impnlsing' re- 7' leases-{for eech iinipiilse thereby "repeating lay' 20 1 I of -the Itrunk circnitffef 7 2] re the impulses through theiwindingf of relay 3 312- in e' circuit extending from ground at the l0wer back 3 contact of relay 204; the; in- I 'termediate lower front contact of relay 206, .wiper; 313', the upper intermediate front cont'a'ctbf relay 307, winding of relay'319,inner upper-heckrcontactiof relay 3'14, back-cone tact of relay to 'hattery thrdugh the Wind 'ing of stepping rnagnet 31.6 of theiregister 310,- }Re1a,y 312 15mm in'this fcircuit and, being slow; tefrele'ase .rerneins energized di r v ingthe'transmission ofth'e, series of impulses 7 Opens the prei'riously 15 traced A of "relay Q 210 *Wh' and at its back Contact c h' th e p n deen'ergize s and shunts;

Fer s overv th r percontac d'ucters 607 Yandf608 '0i7e11':its f onticontects 1-thenceestraced to the calling line. A dial- 7 ing tene'is,t-rtnsmitted overgthis circuitwhensumedmliat the number or {the Wanted" line is 74125, indicativeof a linevvhich"mey be g H v v w indingbf relayl ZlZ i fQIIi h eeine runk il e' pf thebetterjrepetition of impulses: e le gin ;tr'ufikxcircuiti1*At itsnp' the cutgoing trunk circuit 207,52Q81 thereby operating iimpulse' repeatingl -relay 604. ,-Re-

lay; 604 in turn :repeatsimpulsesabut Over trunk" condiictors 607,608 andrepeats: inrpulses to the; stepping magnet .716 Of regis-t ter1-710 of Fig. 7. The. firstdigit-dialed thus 'sets the registers 310xand i710- intd theiri seventh 'p'osit'icns'; Upon the terminetionof r K the impulses irelay z3 l2 releases and closes :a circuit for relay3l5rextending frbniibattery,

Winding pf relay 315,- ofinorrna'l terminals end Wiper 309 of register"31 0 ,"normalitei' Ininel' and Wiper 311 cf register 320't'o 'grdnnd at the back contact of relay 3l2, Relay 315;

energizes and locks over} itslower; centect t6 grqnnd applied to cor' cluctor 353 atjthe-upper front contact of relay 307; and switches the impnlsing circuit previonsly traced 'frem'the lwindingof magnet 3167301 register 310 ever the-upper back 'contactcf relay 322 telthe 85 Winding- 0f1nagneti317 (if register 320. 5 Siniilar'ly relay gnz and 715 function to prepare the registering device ef -Fig:"7. to register the second series of impiilses upon its regis ter'720.

I The second digitzfour dialedby the calling subscriber now sets the register 320 tolits fourth terminalv position, Immediately the second digit register 320 moves" ofi" normal, the rotat-i'onof translator switch 330is started" by e circuit? extending fremfljattery, I through the ttind'in'g and interrupter contacts of mag; net 318, the 1 off-normal terminalsfand Wiper I 319, lower back contact efreley -321; lower} g Y back contact of relay 3221M ground' oncon- 'du'cter 353.4'The; terminals-.inthelowermost latorswitch hunt's fpr theg lay 321' operates OVer theci rCnit just traced,

1 2321, but the open ng the circuitofsteppingjmegnet 318; V \Vhnjlthef relay- 312egein 'deenergizesi upon 1 the termination of the? second series of 'im-;' 1

pulses, with' relay 321 jq'perated a circuit is -cl0s e'dff0r relay 322'extending-fr0m battery,

Winding '0f're1ay 322, front Contact 'ofrelay 321, eff-n0r mz l.terminels'and wiper 3110f register 32O t0ffgr0undet thejback. coiitzicto'f relay [312. Relay 322 operates and locks te ground 'on conductor 353.,jsimilar-"operm c V 1 -tiens are performed f simulta-neously in the 1 registering device. of Fig. 7. I

;.-.In esponse to the dialingfe f the third digit erase-v7.99

irelay'; 204 iasibe fiirei traced' througlr the wind of relay 312;.thence overi'the upper front 1 ;.cont'act ofrelay*3l5;the1upper:front Contact 1 ,o trelay1322ito'battery from the winding of stepping magnet 318. v,It"wa's;assumedthat Y ,the third digit 1 was one "and therefore the I 'l' V translator wipers' 'are advanced one step itur 7 ther. iAs-soon as wiper i325:.leayes terminal V j 326, the circuit of relay321isopened WVhen V 1 ie relay 312 again deenerigizes upon vthetermination of the third ".idigit- :series of impulses circuit is establishediforrelay 314 extendingxfrom battery through'the winding .ofireplay'314, inner lower 'front contactvof relay 1 51322, had: contact of relay.321,:.thence as I traced to groundat thefback contact of relay I 312. :Belay 3l4'upon ioperatin'g locks over its inner lower frontvcontact togroundi'on conductor. 1353; jheiregistering devicefiof 1 aoFigf'? is similarly operated.

Theterminalsiofithe EEour upper levels of translator switch .330 are multiplied in :ac-

cordanceiwith the sizeof the various offices of the exchange and. are jumpered to the points 336,337 and 338 in accordance withi'the' 'distance ibetween the originating ofiicezandlthe iother ofiices. It will be noted that theieven numbered terminals of; the bank associated i-with fwiper .34liare multiplied flIO theuwiper so switching relay and that "as ith'e second duigitidialed was four'r orfof even. yalue, relay 333" is operated oyer wiper 341 andsthefinner upper; front contact offr'elay 322.. .zIn addi-' 'itionthe sixthandpse enthiterminalslinzthe' F bank ofregister3101to1 which wiper 342 has ,"access are connected toe the armatures: oit'zrelay 333*and in accordance'withithe energized I or ,deenergized condition of thisvrelayyare connected to either Wipers "and: .34 for it has been assumed-that theiregister;310=was -set into its seyentlrterminal position andithat relay 3331s operated, wiper i344 onlyfliszconi'nected in a-'circuit over wi'per 342, the lower front contact-act; relay 322" to :ground (incon- "ductor' 353.**$ince also the? translator has been advanced :to position its .{wiper 344 (upon terminal 347; this circuit is extended .bya'j uniper. to j cross connection. point; 349 and thence sotobattery through the winding ofrelay332 as soon as:relay 322' operatesftollowing'the.

termination ofth'e third digit series. lRelay 332upon 7 operating now establishes a circuit 401* relay 215 extending over'wiper 356, theto intermediate upper contact of relay 3.32;back 7 contact 'ofrelay. 331 to ground on conductor 353:- ..At its 'upper fronteoontacta relayw332 a: closesza circuit extending.from'iground; over the inner upperfifront contact.- .ofi relay O7,

-; wiper 308 to battery throughfithe'windi-ngs 1 of relays :210Yandt211,1 therebyi' causing the operation of these Jrelays. @It having 1 been assumedthat connection' is to"; be z made with the line of $106211: subscriber;whichiinay; be"

j "(i reached over thewipersiofgroup selectorgllfl;

:.l ines,uit' is known after the :first two digits .hayeibeen received whether the call is local 1 to the tandemgroup. )If the call'isnot local, a circuitisuestablishedfollowing. the operation ofzrelay 714rwhich may be traced-from 9 battery through the winding of relay 613,

1 normal-terminals and Wiper 348 of register 320, .backcontact'of relay 307 to ground at ;.the ofi enormal contacts 354 of translator no 1crosseconnection:isiimade ibetween termi- 1 nal 347 and .the cross-connectionp01ntsi336,

'337izand i 338 land =i therefore relays 213, 214 and 339areinot operated at this time and no ,IdiScriminatingsi'gnaI is therefore sent to the districtlinkicircuit over conductor216 upon the operation of-relayl 215. I =1 .At the'registering device of Fig. 7 thereg- "iste'rsi'710 vandl720thave been set'in accordance with the-first two digits dialed and' the translator is set. in'the samemanner as de- 7 :scr1bedmore in detail 1n connection-with the setting" ottheregistering device of Fig. "3. 1 Since each tandem.:group is allotted 1000 wiper? 34, back contact of relay-727,. inter- :mediate lower vfront contact of relay714 to ground over conductor 753 'and the upper 100 'At is upper back contact, relay 215disconnects battery potential from conductor 1201', thereby releasing relay 117 in the link wcircuit, in'turnreleasing relay 123. The release of relay 11 23'in turn "opens the circuit of relay 204'in the trunk circuit ofFig.-2, .releasingrelays'205and 206 and relays 3O5 and 307 of the register circuit o'f Fi'g 3. The

release ofcrelay 307 removes holding ground 7 fro'm'conductor 353, thereby releasing oper- C110 atedrelays 314., 315, 322 and 332 and in turn ireleasing relays 333 and 215. A circuit is now establishedfor'restoring the register 320 extendingv from battery, through the winding 7 and. interrupter contacts of magnet 317, offswitch1330. -When the register 320 reaches llOlfIIlZll'illlG operating circuit for magnet 316 (120 Y of-register 310 isrestablished from battery, 'througlrthe Winding and interrupter contacts .of' magnet316;. wiper 349and the oft-normal terminals of the bani: with which it cooper- "atesft-he normal terminal and wiper 348 of L register 320, th enceto ground as traced to oft-normal1contacts 354. Wheirthe register 310 reaches normal the operating circuit of magnet 1 of translator switch 330 is 'established fromibattery through the'winding V iancl interrup tier contacts ofinagnet 31S,;the

lno'rmal' termlnal 3116..W1P8Ii1349 fof 'register 310, thence as tracedito'fgroundf Its restoriing ;circuit. is opened i .when the translator" v a reaches e normal and- [opens contacts:* 3 54 Trunkiinder 300 has nonormal position and remainsin contactwith the terminalsof the gtrunk circuit lasttusecl. All apparatus of the l jvpreviously traced through the windings of trunk circuitlof Fig.- 2: and register of Fig.3

":i'sfnow innormal'condition;

,ijUpon the: release of? relay 204 the circuit 2 Trelay604 is opened,whereupon thisrelay. re-

V leases, in turn [re .fo'f-the-trunk circuit-of Fig; 6 and re1ay;.7 0 5v and 707'. 1dlffhle' release of relay/707; initiates the release of. all operatedapparatus-ofthis registering device infthesame manner. as. previously 'de- ,scrihed'in connectioniwith Fig; 3;!Re'lay 606 leasing relays, 6 0 5 and 606 of the registering device of 'Figt ii.

upon releasing also i opens the circuitpre ,Viously traced for relay ,421 and this relay V releases,qremovi ng holding ground fromithe :winding of relay 414. Also relay422 is again connected to the-incoming trunk conductors 207 and 208 by the 'releaseof relay 421 which lay'126to ground over conduc't0r138and the upper front contact of. relay. 109. l Vhen the does not operate at this time since these trunk f V conductors-have been opened at the district 'linkcircuitrTherefore there being-no holdcircuit effective for relay 414, it releases,

removing f holding ground; from' -conductor 430'and thereby releasing all operated relays 5 'ofthe tandemjlink circuit. Line linder=400 and group selector {410'Ibeing of the non j housinggtyp'e remainjin;their' 0perated posir tions. 1 7, ,i-

; 1-At the "district link circuit ;of VFig. :1 upon Ltherelease ofsrelay 123 thewindings of relay "1 26 are connected theconta'ct's of-relay109iibefore slow'to re vleaserelay124has h'adtime to release followin the release-jofzrelay1235 and a new holding; circuit for relay 124 is therefore esto the calling line loop over tahlished, over the upper front contact ofrecalling}subscriber' now"dials the tens digit which wasassumedtohe two, relay 126 releases for each impulseand establishes a circuit for the tens marking switch magnet 132 which; extends from I battery, through -ithe Q impulsesterminates *7 As .s on as the marking switch 140 leaves c {mmairhe gro p selector- 110;,starts hunt' Q. ing by, reason pf a-circnitfOr;its-stepping sesxt fi gi rqm b y;

winding of magnet'132, lower back contactfio'f ;;reflay 133, winding of relay 134, back contact g-tion of relay 1265'ba'ck contact ofrelay 126 to relay 113 which releasedfupon the opera ground on-conductor "138." :Sl ow to release I relay;1340'perates-in series with magnet1 32- and remains operated until thetens series of through-the the units digitfive. 'Relay 136 locking. contact and lower winding and back contact ofrelay: 145 to off norrnal ground on over 'its inner lower front contact to; ground at theba'ck contacts-of relay l42fand changes theimpulsingcircuit controlled by relay-126 7 from; the winding of magnet 132 to the Winding of magnet 1390f units markingswitc'h 150 whichis now set in-responseto the dialing of conductor-13819:; V

Whenthe group selector;110 reachesthe terminal 142; of its marking: levelmarked by 1 i the setting of the tens the marking switch. having been positioned in position 2, alcircu it is iestahlish'edjfor relay 117 which may lie-traced frombattery,;oif-

marking switch 140,

l'ocksover its normal terminals and wiper 141 of? marking switch 140, winding ofrelay 117, wiperil2l, n terminal 117.0; wiper 119 to ground atthe per back contact f fr'elayF1-18; 1 Relajfll? 7 now opensithe circuit of the. stepping'magnet11'l4of'the'group selector and closes the";

circuit of relay 118 extending from battery, through c the upper winding of 133 to ground. atitheffront contact of relay 117g;,R elay 51118" then' locks over 'its lower winding; and innen lower '7 front ofi normal'ground on; conductor 138 and "switches marking ground; ati 'itsupper con tacts from conductorfll9 'of marking switch 1140 130 thewiper" 143 offthe unitsi'of marking switch 150;- Until the "marking;- switch '150 7 moves beyond its first terminal position relay 117 is held operated ifrom ground over wiper '143, wiper '119, terminal ;170,;wiper 121, thence astracedthroughthewinding of relay 117 t0'batteryatwiper14l so that if the. units further.

digit is one thegroup selectordoes not move- It has been'assumedihowerer,that

I relay 11 8, the upper intermediate front I contact of relay digit-dialed was' five and':therfordwhn marking switch 150 movesbeyonclpos'ition 1,' relay 117 releases and closes ,;the; circuit of magnet ll4-of thegroup selector to; advance it one step1where'upon relay 117 again'o'per teas; In this'manner the group selector fol- "lows the setting ofgthe' unitsmarkingsWitch 1 step by=step :WVhen.the'units 'series of impulses ceases, relay 134- again deenergizes' and from battery? through the winding nf relay l ap-swam? m na 399 ip -51 3 establishesa circuit for-relay l42;extjending' the units .marking iswitch 150, lower front j contact of relay 1'1 8,Y'ofi'f-normal terminals 7 'and'wiper 137 of tens marking switch 140,

back contact "of-relay" 134, inner upper-front contact of relay 118 tofg'round "at the frontcontact of relay: 117. Relay 142 opens the looking circuit ofrelay 1'33 anddurin'g. the

releasingtiine of slow to release relay'133 a circuit is established for thetestrelay. 146 .1

{ :through the cut-off relay 148. If the Iine is' idle, relays 148 and 146 operate andrelay 146 looks over its lower winding and intermedi ate lower contactjito ,ofi-normal ground on conductor 138. At its' upper front contacts relay 146 switches through the talking connection from wipers '127 and 131 through condensers 149 and151, back contacts of relay 123 and front contacts of relay 109 to wipers 128 and 129. 1 At its inner lower front contact the test wiper 122 is connected to test wiper125 so thatthe cut-01f relays 103 and 148 of the calling and calledlines are con- ;nected in parallel through the winding of'relay 109 to ground-at the front contact of relay Ringing current applied to the called line from theringing current source 7 152 through the winding of ringing cut-off relay 145, the upper front contact of relay 136, the inner upper front contact of relay 146, wiper 131, thence over the called line 160 and through the sub-station bell returning overwiper 127, the upper front contact of relay-1'46, the innerupper front contact of J relay 136360 ground at the lower front contact of relay 142 A ringing tone is transmitted to the calllng line over the upperback contact of relay 133, condensers 153 and 151,

thence as traced overlthje calling line. When the called subscriber answers, relay; 145 en- :ergizes releasing relay 136todisconnect the source of ringing current and ringing jtone and to connect the windings of the back I bridge relay 154 to the conductors of the #5 a. V c

I circuit extending from battery, throughjits called line. Relay 154vnow operates-inn -lower winding, upper'back contact of relay I136, innerupper front contact of relay 146,

wiper 131, thence'over "the called line, re-

Y f turning over wiper 127,]thei upper front conf tact of relay 146, to ground through the upper winding of relay'154. f

' V A circuit is now effective for operating the calling linemessage register 155 which may be traced. from ground, through the winding of message register magnet 155, wiper 156,

throughthe inner lower back contact of re' lay 136. Upon the termination of the conlower frontcontact of relay 146 to battery mal condition.

103'and'1'48 of the calling and called lines.

\Vith relay 1% deenergized, a restoring circuit, is established for marking switch 140 extending from battery, through the windand'interrupter contacts of magnet 132,

'ofi-normal, terminals andfwiper 157, to

ground at the back contact of relay 124. 1

When switch 140 reaches normal the winding of magnet/132 is disconnected from jwiper 157 and groundfrom wiper 157 is extended o er wiper 15,8 and the off-normal terminals of its bank through the interrupter contacts and magnet winding 139 of marking switch 150. Switch 150 is thereby restored to normal in which position the circuit of magnet 139 is'opened. 'Grroup selector 110 returns to normal upon the seizure of the link circuit for the next call.

; If the calling subscriber holds the line for thirty seconds after the called subscriber restores his receiver and releases back bridge relay 154, a circuit becomes established for the thermostatic relay 112 extending from battery, through the winding of relay 112, the lower front contact of relay 126, the upper back contact ofrelay 154, the inner upper back contact of relay136 to ground at effective to connect battery over the upper contacts of jack 107, wiper 111, the back contact of line relay 102 to ground through the upper winding of fault relay 159. Relay 159 upon operating looks over its lower winding in a circuit extending over the calling line to ground at vthe upper contact of relay 159, and at its inner upper front contact connects a shunt over wiper 125 thereby causing relay 109 to deenergiz'e and release the connection; [The calling line cut-off relay .103 is also operated by relay 159, thereby prevent ing'the line relay 102 from reoperating and an alarm circuit is closed over the lower contact of relay'159 to apprise the attendant that the calling-subscriber has not restored his receiver as he should. As soon'as the calling subscriber, hangs up, relay 159 releases and restoresthe calling line toits nor- In the foregoing; description it was assumed that the wanted local linewas reached over tlie"wipers of the groupselector 110.

Had the "called subscriber dialed 73125 for reaching a local line terminating ingroup selector 120 or 64125 for reaching a local line terminating in group selector 130, the connection wouldbe established in the manner fully described in our copending application, Serial No. 234,215, filed concurrently herew th. Since the manner in which such the lower front contact of relay 142 which is a lgszopeo 1 .;rams-s also established near battery, through the winding of metering'switch mag- 1 net 223, wiper 224and the normallterminal Cw I upon Wh-ich itfis resting; contact .225Loffthe time switch 222 to ground at the intermediate upper front contact of relay 209 for'advanc- I ingfthe switch 200' one step off normal, from which position it rotates through a-single As-soon as the time switch222 leaves normal e'rate'd as previously described, when the fwiper 227 of the inetering switch 200 passes over the fir'st, third and fifth terminals of 7 its 1 bank three; metering impluses are trans- 'mitte'd over a circuit which extends from metering battery, throughresistance'228, the upper. front contact' of relay 214, terminals and wiper 227 of switch 200, the lower back "contact of relay215, conductor 216, wiper161, the lower front contact of relay 123, wiper i 156 to groundthrough the-message register f'magnet'1'55} These impulses are then followed by two further impulses transmitted from battery, throughresist'ance228, the low erffront Contact of relay 213, the seventh and ninth terminals and wiper 227 of switch 200; fthence as tracedthrough, the winding of rnessag-e "register magnet 155. r

after three minutes, time "switch222 ages.

1 closes.contactf225 and'the metering switch 200 again cOnipIetesa cycIe transmitting five additionalmetering impulses. This sequence of operations continues" if the connection is still helcl' for conversation until nearly twelve min te's have elapsed. Ten seconds prior to the completionfof the twelve minute peifiodQ-the timing switch 222-closes contact1229' connecting a source oftone to'the calling l ne as a warning that the. twelve minute period is '1 about to elapse." If the calling subscriber windings of relay 20tl Relay 204: then 'releases in turn releasingrelays 205 and 206.

Following the release of relay 206 the trunk circuit ofFigs. 2', link-circuit of-Fig. 4, trunk circuit of Eigpfiiand all apparatus which has been taken into'u'se thereby is released;

giZes. 11f the calling subscriber does not now- Relay 123 fuponreleasing now connects the calling line f as previously described to. the

windings of relay 126 whichth'ereup0nenerfrestore his receiver within thirtysec-onds, the thermost atic relay'112 operates overthe'low or front contact of relay 126, .thenormal tor F the calling line message register ma minaland wiper 137 ofimarking' switch 140,. :the-backacontactof relay134,-a back contact of relay 118 to off-normal ground on conductor 138. As previously described, relay 112 causesthe'operation of the'calling line I :fault. relay 159 which signals the attendant and causesthe release of the district link circuit; i I cycle under'the controlof-interrupter 226. 2

1'0' M y t 7 lt opens'eontact- 225so that when the meter- *in'gswitch 200 reaches normal its advance is I a-rrSted-{ With relays 213 and 214=bothop conversation prior tothe completion of the twelve minute perio.d,*the restoration of his receiverxreleases. relay v204 followed by the release of relays205 and206 and the restoration of the remaining equipment. employed" in' t-helconnection. .-If,-however, the calling subscriber holdsjthe connection after the called subscriber hangs up, for a period of thirty seconds, a circuit is established .for the thermostatic relay 217 extending over the lower back. contact of relay 212; whichreleases whenthe called subscriber hangs up, thence to ground atthe lower front contact of relay 220. After the expiration of thirty seconds, relay 217 closes its. lower contact 1 thereby connecting direct ground toiconductor 201 for shunting down relay 117. The

' forced release of the connection is then caused in theimanner previously described. Similarlyafter the out pulsing loop over trunk conductors 207 and -208 is established by re.

lay, 204', if pulsing does not begin the circuit of, relay 217 is established over the upper back contact of relay 211 and. the inner upperv front contact of relay 210 for a sufiicient intervalto cause relay 217 to start the forced release of the established connection.

In the preceding description it I was assumed that both meter control relays 213 and ;214 were operated and that thus for each unit IJQI IOd'Of conversation five metering impulses.

were transmitted by switch 200 for operating gnet.

Had .nietencontrol relay 21 1 been operated alone itis obvious-lthatbut three metering impulses would have been transmitted andthatwsimilarly had relay 213 been operated alone but two metering impulses would have been transmitted.

OaZZ initiated at tandem 077506 for u load I subscriber when. a eaiiis initiated on a line local to the tandem ofiice, assuming that such calling line is similar toxthe callin'gline 101 of Fig; 1 and appears in the bank of line finder-400 of Fig. 4, the line relay of such line closes the circuit'of common start relay 4.03 and all line finders having accessto. that line arestarted. If it is assumed that the finder 100 is the finder whichisto be .used,its operating circuit is 1 controlled 'in the manner previously described and when it seizes the calling line the link finder, 500 is started-to associate the ;.registerxsender of I Fig. andj thegroup -selector.4; is operated to seize anoutgoing thef iiramra previously fclesdri'b ed. l QWhen' a trunkfforhexample, the trunk shown in Fig; 6, isseilz ed"aiiidleilregisteringldevice such asi th'at" shown; in Fig. ,7 is associated therewith in themannerpreVio-uslydescribed.

"As soonas the apparatus associated with the (distant end of trunk '607:-608 isi ready to 7' receive impulses the calling subscriber receiyes a' dial tone as" previously; described I ;;-=S in@e the calling-{subscriber I ishes "i i ,con- 2 f; nection with asubscribers' ,linewhlch termi- 3116. whereupon he commences to dialithei digitsof theWantie'dlinenumber.

I V r T 'n'ate's Iin:--tl'ie tandem oilice,it:will kbe assumed I 1 that he dials the'fnunlber'63256and' lthatin- 7 response tothe first two digits; :registers- 7-10 and 720 are positioned respectivelydn posi- I ,tions-six andi thiree andlthat following the --.'setting of the register 7201 the: translator switch 9730 is started" to hunt for "the group of;term-inals marked by'the wiper '723lof the -register 720. 3 Since the register '728-isin I engagement with its third terminal the trans- T 726 when the further movement or" the trans lator undercontrol of its wiper 7'25 will advance funtil the wip'er 725' engages terminal latorfwill be arrested the operation of 7 wa .721; Following the termination of thesecond-digit seriesrelay 72-2. operatesfand: "locks to'f:ground onfconductor T53J-Y-These I "T operations are allperformedfl in the manner set forth in detail in/connection with the description of Fig I Withfre1ay722' operatedxa'ndr the translator Wiper v in engagementwith terminal .754, which terminal is commoned to the succeeding nine terminals of the same levellcor- 'respondingltothe tandem group of l000l1nes,

a cir'cuit is established.for 'relay 732 extendi'ng from battery," through the winding of relay 7 32, cross connection {P011116 749,. termi- -nalf7 54, wiper 745',"upper back' contact of I relay1733, wiper f 742i of register/Z 10 1 n='-jposi- "tion six, lower front contact of r'elay1722 to jgr oundcn conductori'7 L Belay/Z32 upon; 1 operating establishes a circuit for; relay. 6 15 r i extending over wiper 747,. the intermediate upper 'frontjcontactof relay 7 732," back co'ntact of relay-731 togrfound onconductor, 75.3.v.c Relay j615 locks over itsfupper lfront contact i 1 togroun'don conductor 621 and at ts upper back: contact removes; busy potent al from terminallthereby releasing relays425-and I 428 in -thetandem linkcirCuitg With relay 7 .thefwindings of; relay thef bonductors oftthe cal-lingsline over front contacts; of

Eollowing the release 0f r ay ri n for-holding" relay .414 op d i s pp ed -from 'i the "front contact of relay -1- 4221 (The group selector 410 in addition; to hayfingv access to outgoing trunk circuits. also has access; to groups of trunks. terminating in third group 1 finders; vThe terminals of :the c bank leyelito IWhlCh. wiper 1427 has access, which ccrre'spondto third group finders, are

--commonediandconnected toa conta'cton relay 438. we *Sincefrelay 438 operated in a circuit" extending, through its winding, lwip'eri 515;

'upperback contact of relay 1514 tojground 1 onconductor 5 53,.upon the seiz ureofthe link circuitgby the link finder1500, these comrnoned 1 terminals are connected over the inner upper front contact ofrelay 43 8, upper front "contact of relay 426, throughthelower winding of testrelay 425 to ground at the inner upper ZrGlayAOTFand'linefinderwipers 418 and 419;

front contact of relay4l2. The group selector i group finder a circuit extending from bat back contacts of relay 424, back contacts of ,trelay425zto ground at the front contact of relay 407;; 3 When an idle third group jfinder 4410 is now started ta-hunt for an idle third ltery, thr'ough=the winding andinterrupter 1 contacts of magnet 423, i intermediate upper is found relay 425 operatesin thecircuitipre viouslyi traced to the strappedterminals of .group fselector 410,-thenc'e ovei wi'per 427,

inner s upper; front contacts of; relay 1426, wiper 435 to battery potential on-test terminal 439-:of thetrunlr terminating inan idle third group finder; ZEelay425 upon operating locks as before described over its upperfwi'nding in series: withjrelay 428. r

" vRelay'428 upon operating establishes a circuit for relay-424 extending from battery, through the windingof relay 424, lower front Qcontact'of, relay43Y, which operated in'the locking circuit of'relay 426, to ground at the Zfront contact of relay-428. .The tandem link 'circ'uitis now in condition to receive the-last thedialing of the' first of these.digitsrelay 422 functifo'nsas a repeating relay a'nd upon each.

deenergization repeatsan mpulse overa circuit which maybetracedfromgrou nd atiits backcontact, upper tronticontact 2 of relay 437, wiper 516;, lower front ic ontact ofrelay 507, winding of slow to release relayfl5l7. to

batterytliroughthe winding of pulsing relay.

518.- Relay 518 inturnrepeats impulsesoyer a. circuit-extending from/its lowerjfront' contact, lowerback contactlof;relay;5l4 to bat- V tery through thevw-inding of stepping magnet 519ofthehundredsregister 510. Atj the' end of the first series ofimpulsesrelay 517; de-

energizes .andestablis'hes a circuit for trans- .ferrelay- 5 14 extending frombattery, through thewindingl and inner lowernormal contacts [three digits-ofthe wantedline number which I ihaveabeenassumed to lee-256." In response to I 9; now repeats .impul'sesto the magnet 522 and attheend of thisidigitseries relay 523 oper-' I v '1 p of relay- 514, 'oif-normalterminals, and wiper 521 of register 510 toground at the back contaet'of relay-V517; 'Relay' 514 operates and locks to ground, on conductor 553 and trans fers the impulsing circuit from the winding jofistepping magnet 519: tothewindingof; ,stepping magnet 522- oftens register520y over,

i the lower back contact'of transfer relay 523.1v

In'response to thenext digit series relay 5l8- ates circuitextending from battery,

' throughsits winding and upper normal con- 2 5 digit series relay 518i, repeats impulses to the v tacts,'oii'-normal terminalsand wiper-5240f register: 520 to ground "at the back contact of" relay5l7. i' Relay523'thenlocks to-groundon "conductor'553 and transfers the pulsing cirfcuit. from vrnagnet 522 to magnet 525 of the units registert53O. Inrespons to the .la St stepping inagnet525o. l The; registers 510,, 520

and, 53o have nowibeenfset to; register the is s'ase, I

' A soon as vthe register registered the 'lirst;1 of these digits 'a circuit is closed which may be tracedfrom battery, over the lupper front contact; of relay I514, inner upper loacl: contact of relay 526,- inner upper back contact of relay. 527, upper back contactof reiaysee, intermediate lowerfront contact I I 1 ofrelay"507,wiper 509, inn'er upper front. contact 'ofsrelay 424.;10Werback con-tact ofrei lay 440,'-towiper-F434, thence to ground througha control relay in the third group not shown. f VVhen the group finder 1 I ready toreceia e'impulses from the sender of p o front contact of relay 434, wiper 531, inner Fig.5, acircuitis established'by thecontrol' 'relay ofithe group finder extending from battery thereat to thiewiper 431,.thence over the upper back contact of relay .440, the lower 1 lower 7 front contact of relay 507,- inner upper normal contacts of relay 528, ilower normal contacts of relay, 527': toground through the winding :ofrelay 532. Belay 532 thereupon operates and 7 extending from loattery,,w1-nd1ng of relay 52?, contact of; relay 532. to ground over the l normal terminal 533sand wiper 534 of nnpulse counting switch 540., ;Relay*527 thereupon closes aI-circuit forlrelay 527 locks over its lower front contact to ground .c over the segment 535 and wiper 536 of count 1 ing switch 540 and releases relay 532. Atits I inner front contacts relay 527 also extends the circuits previously; traced from wipersi434 'and'431 in a closed loop over wiper 542, of

"switch 540; At its upper frontgcontact relay 7 527 also establishes an: obvious operating cirterrnpting; the: impel 6b cuitforgstepping magnet;'538 ofswitch-549 whereby the switch. operates step bystepyin loop e'xten ding to V the third -g'roupF finder'fat thewi-per 542- at 7. each step.

FWhen the wiper-534 the 539 narlredby tannins-L541; of register 5 51 0,,

which it has been assumedhasbeen positioned in position two,aci rcuit is established from i ground, over Wiper 534, terminal I 539, wiper 541, upper backcontact of relay526 to batteryzthrough the winding of relay 537. Re-

lay537 1operates closing a permanent loop of the'outpulsing circuit in shunt of the wlper 542 thus stopping the transmission to the group finder of effective stepping impulses;

Relay 537 also locks over its lower contact to ground over ofi-normalsegment 535 and;

wiper 536.,yWhen the switch540 advances beyond-segment 543 the loopis closed over wiper and segment 544. When wiper, 536advances'beyond segment 5351 the holding circuitsof relays 527 and 537 are opened and'these relays release, but switch'540 continues to; advance into its normal position by.

means of a circuit closed over its off-normal switch, contacts 545. When the wiper 534 passespverthe, terminal 546 an obvious cir-' cuitfisclos'ed for relayw526 which locks over its-innerlower front contact to ground on conductor 553. The operation ofthe third group finder has thus selected a group of is ready to receive impulses of the tens digit it fconnects battery' over the clrcuit established therefromto the wiper 431, thence gas traced to vgroundthrough the winding ofrelay 532.51Relay532 again operates in this circuit and in turn operates relay 527 to close the o'ut pulsing loop over wiper 542 and startstfhe impulsing switch 540in a second revolution, When wiper 53'4leaves the ter-' 'minal 533,-r'elay 532 deenergizes, but; relay 527 is held operated over wiper 535 and segment 535; As soonias wiper534 reaches the select-or, notshow-n. 1 VWhen the final selector 5 terminalZ-of the lower level of oswitch 540 upon; which -marking potential has been placed byw'iper548 oft'he tens register 520,

p which itowasassumed has been set into, position five, a-cirouit is efiecti ve from ground on wiper .;534,;over wiper 548, back contact of relay 549,, the upper front contact of relay 526 vto battery through relay537. Relay 537 operates andperforms the functions previouslydescribed Switch-540 advances to its normal position and in passing terminal550 establishes acircuitfor relay549 extending from ground,;wiper 536, terminal 550, lower front 'contactofrelay 526-to battery through thewinding o-firel'ay549, Relay 549operates and locks over itsupp'er contact to groundon conductor 553.?1'1 y, 

